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Autoimmune thyroid diseases (AITDs), including Hashimoto thyroiditis and Graves’ disease, are the most common autoimmune endocrinopathies, affecting up to 5% of the population. Pathogenetic pathways have not yet been fully elucidated, even though different immune-genetic alterations have been proposed. Specific immune defects presenting with AITDs may serve as an experimentum naturae to study the involvement of a specific pathway in the pathogenesis of the disease. In fact, since immune dysregulation with autoimmunity frequently characterize inborn errors of immunity (IEIs), understanding the mechanisms of immune tolerance breakdown leading to autoimmunity in these conditions may provide useful insight to understand the pathogenesis of AITDs. In this review, we will highlight the main immunological aspects of AITDs and their pathogenesis in IEIs.

Wiskott-Aldrich syndrome (WAS) (MIM #301000) is a rare X-linked primary immunodeficiency due to mutations in the WAS gene, characterized by thrombocytopenia with small platelets, eczema, recurrent infections, and an increased incidence of autoimmunity and malignancies. A wide spectrum of mutations has been identified in the WAS gene responsible for a broad variety of clinical phenotypes. By using targeted next-generation sequencing (t-NGS), we identified in a 2-month-old boy with thrombocytopenia and immunological alterations a 4-nucleotide deletion from position +3 to +6 of intron 8 (c.777 + 3_777 + 6delGAGT) of WAS , currently classified on ClinVar as a variant of uncertain significance. The in-vitro characterization of the variant revealed the complete retention of intron 8 in the mature transcript, suggesting a splicing defect due to the loss of a splice donor site at the 5′-end of intron 8. By sequencing the polymerase chain reaction product, we identified a premature stop at codon 269; thus, consequently, no Wiskott-Aldrich syndrome protein (WASp) was detectable in peripheral blood mononuclear cells from the patient. Due to the total absence of a full-length WASp, it is expected that the patient will develop the severe form of the disease, although further monitoring is needed to better define his phenotype.

Background and aimsWiskott–Aldrich syndrome (WAS) is an X-linked recessive primary immunodeficiency disorder characterized by severe eczema, recurrent infections, and micro-thrombocytopenia. Allogeneic hematopoietic stem cell transplantation (HSCT) is a potentially curative therapeutic option for patients with classic form. The risk of developing post-transplant tumors appears to be higher in patients with WAS than in other inborn errors of immunity (IEIs), but the actual incidence is not well defined, due to the scarcity of published data.MethodsHerein, we describe a 10-year-old patient diagnosed with WAS, treated with HSCT in the first year of life, who subsequently developed two rare solid tumors, kaposiform hemangioendothelioma and desmoid tumor. A review of the literature on post-HSCT tumors in WAS patients has been performed.ResultsThe patient received diagnosis of classic WAS at the age of 2 months (Zhu score = 3), confirmed by WAS gene sequencing, which detected the nonsense hemizygous c.37C>T (Arg13X) mutation. At 9 months, patient underwent HSCT from a matched unrelated donor with an adequate immune reconstitution, characterized by normal lymphocyte subpopulations and mitogen proliferation tests. Platelet count significantly increased, even though platelet count never reached reference values. A mixed chimerism was also detected, with a residual WASP− population on monocytes (27.3%). The patient developed a kaposiform hemangioendothelioma at the age of 5. A second abdominal tumor was identified, histologically classified as a desmoid tumor when he reached the age of 10 years. Both hematopoietic and solid tumors were identified in long-term WAS survivors after HSCT.ConclusionHere, we describe the case of a patient with WAS who developed two rare solid tumors after HSCT. An active surveillance program for the risk of tumors is necessary in the long-term follow-up of post-HSCT WAS patients.

X lymphoproliferative syndrome type 1 (XLP1) is a rare inborn error of immunity due to mutations of , encoding for slam-associated protein (SAP). The clinical phenotype includes severe mononucleosis, hemophagocytic lymphohistiocytosis (HLH), and B-cell lymphomas. We report the case of a child affected with XLP1 who presented with an incomplete HLH, triggered by Epstein-Barr virus (EBV) and treated with rituximab, involving orbits and paranasal sinuses. The lesion was indistinguishable from lymphoma, complicating diagnosis and treatment. In addition, considering the high incidence of lymphoma in patients with XLP1, histology helped define its nature, driving therapeutic choices. We described an unusual presentation of incomplete HLH in a patient affected with XLP1: an EBV-driven infiltration of the orbits and paranasal sinuses. This led us to a challenging differential diagnosis of lymphoma-associated hemophagocytic syndrome, which can be frequently observed in patients with XLP1. Considering the extremely poor prognosis of this clinical finding, we sought for a prompt diagnosis and managed to obtain it and to immediately establish the right treatment on the basis of the pathological finding.

Background Tracheal compression (TC) due to vascular anomalies is an uncommon, but potentially serious cause of chronic respiratory disease in childhood. Vascular slings are congenital malformations resulting from abnormal development of the great vessels; in this group of disorders the most prevalent entity is the aberrant innominate artery (AIA). Here we provide a report on diagnosis and treatment of AIA in nine children with unexplained chronic respiratory symptoms. We describe the cases, perform a literature review, and provide a discussion on the diagnostic workup and treatment that can help manage AIA. Methods Clinical history, diagnostic procedures and treatment before and after the AIA diagnosis were retrospectively reviewed in nine children (5 boys and 4 girls), who were referred for recurrent-to-chronic respiratory manifestations over 10 years (2012–2022). We performed a comprehensive report on the ongoing clinical course and treatment as well as an electronic literature search on the topic. Results Diagnoses at referral, before AIA was identified, were chronic dry barking cough associated with recurrent pneumonia ( n  = 8, 89%), lobar/segmental atelectasis ( n  = 3, 33%), atopic/non atopic asthma ( n  = 3, 33%); pneumomediastinum with subcutaneous emphysema complicated the clinical course in one case. When referred to our Unit, all patients had been previously treated with repeated antibiotic courses ( n  = 9, 100%), alone ( n  = 6, 67%) or combined with prolonged antiasthma medications ( n  = 3, 33%) and/or daily chest physiotherapy ( n  = 2, 22%), but reported only partial clinical benefit. Median ages at symptom onset and at AIA diagnosis were 1.5 [0.08–13] and 6 [4–14] years, respectively, with a relevant delay in the definitive diagnosis (4.5 years). Tracheal stenosis at computed tomography (CT) was ≥ 51% in 4/9 cases and ≤ 50% in the remaining 5 subjects. Airway endoscopy was performed in 4 cases with CT evidence of tracheal stenosis ≥ 51% and confirmed CT findings. In these 4 cases, the decision of surgery was made based on endoscopy and CT findings combined with persistence of clinical symptoms despite medical treatment. The remaining 5 children were managed conservatively. Conclusions TC caused by AIA may be responsible for unexplained chronic respiratory disease in childhood. Early diagnosis of AIA can decrease the use of expensive investigations or unsuccessful treatments, reduce disease morbidity, and accelerate the path toward a proper treatment.

MyD88 deficiency is a rare inborn error of immunity (IEI) characterized by susceptibility to pyogenic infections without overt signs of inflammation. Half of the reported patients belong to Roma descent, an itinerant ethnic group living mostly in Europe, with an increased risk of childhood mortality due to limited access to healthcare services. We describe three unrelated patients from the Campania region in Italy with MyD88 deficiency, all belonging to Roma descent and displaying severe or recurrent infections in early infancy. They underwent a comprehensive immunological work-up including targeted next-generation sequencing for IEIs that identified a homozygous pathogenic in-frame deletion c.157_159del p.(Glu53del) in MYD88 gene, already described in this ethnic group, suggesting a founder effect. A high level of alert should be kept in patients of Roma ethnicity with early onset severe infections. Moreover, being associated with increased Immunoglobulin E (IgE) levels, this condition should be included in the differential diagnosis of Hyper-IgE syndromes.

Epigenetic alterations, including aberrant DNA hypermethylation and histone modifications, contribute to oncogenesis by disrupting normal gene expression programs. Unlike genetic mutations, these changes are potentially reversible, providing a strong biological rationale for the development of histone deacetylase inhibitors (HDACi) for therapy. Several HDACi are currently under investigation, either as monotherapy or in combination with other anticancer agents. A comprehensive understanding of toxicity is essential to appropriately balance risks and benefits, particularly because HDACi are most frequently evaluated within combination regimens. To date, no epigenetic agents have received regulatory approval for pediatric malignancies, and clinical development in this population remains at an early stage. The aim of this study was to systematically characterize the toxicity profiles associated with HDACi administration in pediatric patients with cancer, including both solid tumors and hematologic malignancies. To this end, we conducted a systematic review of the literature in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Toxicity profiles were extracted from twelve studies investigating six HDACi: panobinostat, vorinostat, entinostat, pracinostat, valproic acid, and depsipeptide. Eleven studies were Phase I or Phase I/II clinical trials, and one was a retrospective study. Patients with solid central nervous system tumors represented the most frequently studied population. Overall, treatment-related toxicities were predominantly mild, with few severe (grade 4) adverse events, mainly within the hematologic category. According to the Common Terminology Criteria for Adverse Events grading system, hematologic toxicities were the most common adverse events across all HDACi, particularly thrombocytopenia, followed by mild gastrointestinal and metabolic toxicities. Cardiac, neurological, respiratory, and systemic toxicities were generally mild, less frequent, and considered treatment-related. Dose and route of administration influenced both the frequency and severity of toxicities. Pan-HDAC inhibitors were associated with the highest rates of toxicity. HDACi-related toxicities were moderate and manageable in pediatric patients. Differences in toxicity were observed among treatments, with higher doses linked to increased toxicity. These findings support further clinical trial development of HDACi in pediatric malignancies. However, Phase I design, small patient numbers, and heterogeneity in age, weight, and disease characteristics are major limitations in accurately assessing HDACi-induced toxicity.

BackgroundHematologic immune dysregulation (H-ID) – including autoimmune cytopenia (AIC), lymphoproliferation (LPD), and hemophagocytic lymphohistiocytosis (HLH) – is a potentially life-threatening manifestation of inborn errors of immunity (IEI). Despite the availability of targeted therapies, its management remains challenging, with no standardized treatment strategies established.ObjectiveTo evaluate the efficacy and safety of the available treatments for H-ID, with a specific focus on the treatment indications and outcome differences between targeted versus non-targeted therapies.MethodsThis multicentric retrospective study included 116 patients with IEI and H-ID across Italian tertiary care centers. Data included treatment indications, response rate, and incidence of adverse events (AEs).ResultsWe included patients with autoimmune lymphoproliferative immunodeficiencies (ALPID, 37.1%), humoral immunodeficiencies (31%), syndromic IEI (8.6%), and combined immunodeficiencies (8.6%). H-ID consisted of AIC (67.2%), LPD (71.6%), and HLH (9.5%). 85.3% of patients received treatment, including on-demand therapies (37.9%), long-term treatments (LTT, 84.8%), and hematopoietic stem-cell transplantation (HSCT; 9.1%). LTT included sirolimus (42.9%), mycophenolate mofetil (34.5%), rituximab (29.8%), and targeted therapies (17.9%). Sirolimus showed a higher complete response (CR) rate (61.1%), especially in ALPID patients and those with lymphoproliferation (72%). CR rate was significantly higher in patients receiving targeted therapies (80% vs 43.4%, p < 0.05). AEs were reported in 13.3% of cases, leading to drug withdrawal in 3.6%.ConclusionsThe indications for LTT and HSCT in H-ID are still heterogeneous. Response rates are variable and influenced by the underlying diagnosis. Targeted therapies are associated with an improved response, the suboptimal molecular diagnosis rate currently limits their use.

Initially described as a triad of immunodeficiency, congenital heart defects and hypoparathyroidism, 22q11.2 deletion syndrome (22q11.2DS) now encompasses a great amount of abnormalities involving different systems. Approximately 85% of patients share a 3 Mb 22q11.2 region of hemizygous deletion in which 46 protein-coding genes are included. However, the hemizygosity of the genes of this region cannot fully explain the clinical phenotype and the phenotypic variability observed among patients. Additional mutations in genes located outside the deleted region, leading to “dual diagnosis”, have been described in 1% of patients. In some cases, the hemizygosity of the 22q11.2 region unmasks autosomal recessive conditions due to additional mutations on the non-deleted allele. Some of the deleted genes play a crucial role in gene expression regulation pathways, involving the whole genome. Typical miRNA expression patterns have been identified in 22q11.2DS, due to an alteration in miRNA biogenesis, affecting the expression of several target genes. Also, a methylation epi-signature in CpG islands differentiating patients from controls has been defined. Herein, we summarize the evidence on the genetic and epigenetic mechanisms implicated in the pathogenesis of the clinical manifestations of 22q11.2 DS. The review of the literature confirms the hypothesis that the 22q11.2DS phenotype results from a network of interactions between deleted protein-coding genes and altered epigenetic regulation.

The epigenome bridges environmental factors and the genome, fine-tuning the process of gene transcription. Physiological programs, including the development, maturation and maintenance of cellular identity and function, are modulated by intricate epigenetic changes that encompass DNA methylation, chromatin remodeling, histone modifications and RNA processing. The collection of genome-wide DNA methylation data has recently shed new light into the potential contribution of epigenetics in pathophysiology, particularly in the field of immune system and host defense. The study of patients carrying mutations in genes encoding for molecules involved in the epigenetic machinery has allowed the identification and better characterization of environment-genome interactions via epigenetics as well as paving the way for the development of new potential therapeutic options. In this review, we summarize current knowledge of the role of epigenetic modifications in the immune system and outline their potential involvement in the pathogenesis of inborn errors of immunity.